JavaScript/TypeScript Practices

Conventions for JS/TS syntax, modules, types, and runtime behavior.

Quick Start

import * as path from "@std/path"; // namespace import
import { utils } from "./utils.ts"; // explicit extension

export function buildConfig() {} // direct named export
const port = config.port ?? 8000; // nullish coalescing

Key Principles

Modules: Direct named exports, namespace imports, explicit

.ts

extensions

Syntax:

const

over

let

, always semicolons,

===

strict equality,

??

over

||

Types:

Number()

over

+

,

instanceof

over

typeof

, prefer

null

over

undefined

Runtime:

import.meta.dirname

,

globalThis

over

window

, optional

projectRoot

params

Async: Use

return await

consistently for better stack traces and correct error handling

Avoid:

eval

, prototype mutation, truthy/falsy checks on non-booleans

References

See rules.md for complete guidelines with examples.